Original bug ID: 6674
Reporter: @alainfrisch
Assigned to: @maranget
Status: closed (set by @xavierleroy on 2016-12-07T10:37:00Z)
Resolution: fixed
Priority: high
Severity: crash
Fixed in version: 4.03.0+dev / +beta1
Category: ~DO NOT USE (was: OCaml general)
Related to: #6646

Bug description

On trunk, but not on 4.02, I get the following exception:

Fatal error: exception Invalid_argument("index out of bounds")

when compiling (with ocamlc) the code below:

type t =
  | A1
  | A2
  | A3
  | A4
  | A5
  | A6
  | A7
  | A8
  | A9
  | A10
  | A11
  | A12
  | A13
  | A14
  | A15
  | A16
  | A17
  | A18
  | A19
  | A20
  | A21
  | A22
  | A23
  | A24
  | A25
  | A26
  | A27
  | A28
  | A29
  | A30
  | A31
  | A32
  | X of string

let f = function
  | X _ -> true
  | _ -> false

Here is the top of the stacktrace:

Raised by primitive operation at file "bytecomp/switch.ml", line 746, characters 2-22
Called from file "bytecomp/switch.ml", line 840, characters 21-36
Called from file "bytecomp/switch.ml", line 862, characters 5-35
Called from file "bytecomp/matching.ml", line 2469, characters 21-108
Called from file "bytecomp/matching.ml", line 2743, characters 28-64
Re-raised at file "bytecomp/matching.ml", line 2717, characters 10-46
Called from file "bytecomp/matching.ml", line 2793, characters 6-145
Called from file "bytecomp/matching.ml", line 2977, characters 30-73
Called from file "bytecomp/translcore.ml", line 1090, characters 7-88
...